In a large mixing bowl, combine lukewarm water, yeast, barley malt (if using), and vitamin C powder (if using). Stir to dissolve. Add the sourdough starter (can be active or discard) and malt syrup or molasses. Mix until well combined. Gradually add the bread flour and rye flour, stirring as you go.

Knead for 6-8 minutes, ideally in a stand mixer, as the dough will be sticky.

Leave to rest for 30min to 1h.

Cover with plastic wrap or a damp cloth. Let the dough rise at room temperature for 3 to 6 hours or overnight, until doubled in size.

Leave to stand for another 30 minutes to 1h, covered with a damp tea towel, while you preheat your oven.

Mix in the cooled melted butter, sprinkle kosher salt over the dough and mix well.

Turn the risen dough onto a floured surface. Fold the dough into 3rds 3 times, turning by 90 degrees each time, to give it some tension. Cut into 8-12 pieces, depending on your preference.

Shape into rolls by pulling and tucking the edged under the bun, creating more tension in the dough, for nicely puffed up rolls later.

Preheat your oven to 375°F (190°C) during the final stages of the second rise.

Brush with some egg white mixed with 2 tbsp water and a bit of honey (or just water) and sprinkle with your favourite seeds. I used sesame and caraway. But sunflower, pumpkin seeds or poppy seeds are all really lovely.

Bake for about 20 minutes or until golden brown and sounding hollow when you tap the bottom.

After baking, transfer the rolls to a wire rack to cool completely. Enjoy these rye sourdough discard rolls as a delicious addition to your meals!